Dr. Martin terms it) never succeeding beyond the third remove from the human into the bovine subject.
There can now, therefore, be no reasonable doubt that a very large proportion of the failures, triumphantly adduced by anti-vaccinationists as proofs that the alleged protective power of vaccination is a mere assumption, are attributable to this degeneration, the protection diminishing with the "humanization" of the virus employed, and this being proportional to the remoteness of its derivation from the bovine stock.
During the war between the Northern and Southern States, Dr. Martin (who had previously acquired a reputation for special knowledge of this subject) was specially employed by the Government of the North to proceed to the various localities in which severe outbreaks of small-pox were from time to time taking place, and he most commonly found that there had either been no previous vaccination at all or vaccination with degenerate virus. Armed with a supply of good lymph, and with military authority (which enabled him to practice a really compulsory vaccination and revaccination), he always found himself able to control these outbreaks, and to prevent their recurrence. Anxious, however, to obtain (if possible) a fresh primary stock of vaccine, he advertised extensively for information as to any original case of cow-pock, but could hear of none. And he then imported from France some dried lymph of what is known as the "Bougival" stock, which had been continuously transmitted, through a long succession of heifers, from its original bovine parentage in that place. This transmission he has himself kept up in the neighborhood of Boston (New England) for the last ten years; and he assures me—1. That vaccination from this heifer-stock, if practiced according to his instructions, is quite as successful (in regard to the proportion of cases in which it "takes") as vaccination from the human arm; 2. That the vesicle produced by it is always of the true old Jennerian type, no deterioration having taken place in its long descent from the original stock, such as is produced by "humanization"; 3. That he has never seen either erysipelas or any other of the "accidents" which sometimes (as in my own Bristol experience in 1838) attend the direct vaccination from the original cow-stock; and, 4. That, having offered a considerable reward in all the principal towns of the Union for information as to the occurrence of any case of small-pox within ten years after thorough vaccination with his heifer-lymph, this reward has never been claimed; although, since its introduction, the United States have been traversed (in the years 1874-'76) by an epidemic of small-pox, which will be long remembered there for its peculiar virulence and the wide-spread mortality it occasioned.
- The distinguished American physicians, whose attendance at the recent Congress gave me the opportunity of conversing with them on this subject, entirely confirmed Dr. Martin's account of the severity of that epidemic, which, in some respects, bore such a